Neurostimulation titration process via adaptive parametric modification

Abstract

Systems and methods are provided for delivering neurostimulation therapies to patients. A titration process is used to gradually increase the stimulation intensity to a desired therapeutic level. Between titration sessions one or more parameters, such as, for example, an acclimation interval, may be adjusted based on the patient's response to the stimulation. This personalized titration process can minimize the amount of time required to complete titration so as to begin delivery of the stimulation at therapeutically desirable levels.

What is claimed is: 
     
       1. A method of operating an implantable medical device (IMD) comprising a neurostimulator coupled to an electrode assembly, said method comprising:
 initiating a plurality of titration sessions, each titration session separated from an adjacent titration session by an acclimation interval, wherein the titration sessions comprise activating the IMD to deliver a stimulation signal of gradually increasing intensity until the patient exceeds a side effect tolerance zone boundary, wherein the stimulation signal comprises a frequency in a range of 5 Hz to 10 Hz; 
 analyzing an outcome measure of the plurality of titration sessions including determining whether the outcome measure indicates expected patient adaptation; and 
 modifying one or more stimulation parameters based on the analyzed outcome measure relative to the expected patient adaptation. 
 
     
     
       2. The method according to  claim 1 , wherein modifying one or more stimulation parameters comprises modifying the acclimation interval until a subsequent titration session based on the analyzed outcome measure. 
     
     
       3. The method according to  claim 2 , wherein modifying the acclimation interval comprises at least one of:
 increasing the acclimation interval in response to the outcome measure indicating slower than expected patient adaptation, 
 increasing the acclimation interval in response to the outcome measure indicating a failure to achieve a target increase in stimulation intensity, 
 increasing the acclimation interval in response to the outcome measure indicating a failure to achieve a target increase in output current over the plurality of titration sessions, wherein the stimulation signal comprises the output current, or 
 decreasing the acclimation interval before the subsequent titration session in response to the outcome measure indicating faster than expected patient adaptation. 
 
     
     
       4. The method according to  claim 2 , further comprising, during the acclimation intervals, activating the IMD to deliver the stimulation signal at an intensity resulting in an acceptable side effect level. 
     
     
       5. The method according to  claim 1 , further comprising:
 determining a maintenance dosage level corresponding to a tolerable stimulation intensity achieving adequate adaptation; and 
 delivering stimulation at the maintenance dosage level. 
 
     
     
       6. The method according to  claim 1 , further comprising receiving a patient input indicating the side effect tolerance zone boundary by at least one of:
 receiving a radio frequency (RF) signal from an external communications device, said RF signal indicating that the patient has reached the side effect tolerance zone boundary, 
 detecting a magnetic field indicating that the patient has reached the side effect tolerance zone boundary, 
 detecting an acoustic signal indicating that the patient has reached the side effect tolerance zone boundary, or 
 detecting a motion signal with a motion sensor indicating that the patient has reached the side effect tolerance zone boundary. 
 
     
     
       7. The method according to  claim 1 , further comprising:
 initiating an elevated stimulation session at an elevated stimulation intensity for a first period of time; and 
 after the first period of time, initiating sustained stimulation at a sustained stimulation intensity for a second period of time, wherein the elevated stimulation intensity is greater than the sustained stimulation intensity. 
 
     
     
       8. A method of operating an implantable medical device (IMD) comprising a neurostimulator coupled to an electrode assembly, said method comprising:
 initiating a plurality of titration sessions, each titration session separated from an adjacent titration session by an acclimation interval, wherein the titration sessions comprise activating the IMD to deliver a stimulation signal of gradually increasing intensity until the patient exceeds a side effect tolerance zone boundary, wherein the stimulation signal comprises a frequency in a range of 5 Hz to 10 Hz; 
 analyzing an outcome measure of the plurality of titration sessions; and 
 modifying one or more stimulation parameters based on the analyzed outcome measure. 
 
     
     
       9. The method according to  claim 8 , further comprising:
 delivering the frequency of the stimulation signal at 10 Hz; and 
 upon the patient exceeding the side effect tolerance zone boundary, decreasing the frequency to 5 Hz. 
 
     
     
       10. The method according to  claim 8 , wherein modifying one or more stimulation parameters comprises modifying the acclimation interval until a subsequent titration session based on the analyzed outcome measure. 
     
     
       11. The method according to  claim 10 , wherein modifying the acclimation interval comprises at least one of:
 increasing the acclimation interval in response to the outcome measure indicating slower than expected patient adaptation, 
 increasing the acclimation interval in response to the outcome measure indicating a failure to achieve a target increase in stimulation intensity, 
 increasing the acclimation interval in response to the outcome measure indicating a failure to achieve a target increase in output current over the plurality of titration sessions, wherein the stimulation signal comprises the output current, or 
 decreasing the acclimation interval before the subsequent titration session in response to the outcome measure indicating faster than expected patient adaptation. 
 
     
     
       12. The method according to  claim 10 , further comprising, during the acclimation intervals, activating the IMD to deliver the stimulation signal at an intensity resulting in an acceptable side effect level. 
     
     
       13. The method according to  claim 8 , further comprising:
 determining a maintenance dosage level corresponding to a tolerable stimulation intensity achieving adequate adaptation; and 
 delivering stimulation at the maintenance dosage level. 
 
     
     
       14. The method according to  claim 8 , further comprising receiving a patient input indicating the side effect tolerance zone boundary by at least one of:
 receiving a radio frequency (RF) signal from an external communications device, said RF signal indicating that the patient has reached the side effect tolerance zone boundary, 
 detecting a magnetic field indicating that the patient has reached the side effect tolerance zone boundary, 
 detecting an acoustic signal indicating that the patient has reached the side effect tolerance zone boundary, or 
 detecting a motion signal with a motion sensor indicating that the patient has reached the side effect tolerance zone boundary. 
 
     
     
       15. The method according to  claim 8 , further comprising:
 initiating an elevated stimulation session at an elevated stimulation intensity for a first period of time; and 
 after the first period of time, initiating sustained stimulation at a sustained stimulation intensity for a second period of time, wherein the elevated stimulation intensity is greater than the sustained stimulation intensity. 
 
     
     
       16. An implantable medical device comprising:
 an electrode assembly; 
 a neurostimulator coupled to the electrode assembly, the neurostimulator configured to:
 initiate a plurality of titration sessions, each titration session separated from an adjacent titration session by an acclimation interval, wherein the titration sessions comprise activating the implantable medical device to deliver a stimulation signal of gradually increasing intensity until the patient exceeds a side effect tolerance zone boundary, wherein the stimulation signal comprises a frequency in a range of 5 Hz to 10 Hz; 
 analyze an outcome measure of the plurality of titration sessions; and 
 modify one or more stimulation parameters based on the analyzed outcome measure. 
 
 
     
     
       17. The implantable medical device according to  claim 16 , wherein the neurostimulator is configured to:
 deliver the frequency of the stimulation signal at 10 Hz; and 
 upon the patient exceeding the side effect tolerance zone boundary, decrease the frequency to 5 Hz. 
 
     
     
       18. The implantable medical device according to  claim 16 , wherein the neurostimulator is configured to modify the acclimation interval until a subsequent titration session based on the analyzed outcome measure. 
     
     
       19. The implantable medical device according to  claim 18 , wherein the neurostimulator is configured to modify the acclimation interval by at least one of:
 increasing the acclimation interval in response to the outcome measure indicating slower than expected patient adaptation, 
 increasing the acclimation interval in response to the outcome measure indicating a failure to achieve a target increase in stimulation intensity, 
 increasing the acclimation interval in response to the outcome measure indicating a failure to achieve a target increase in output current over the plurality of titration sessions, wherein the stimulation signal comprises the output current, or 
 decreasing the acclimation interval before the subsequent titration session in response to the outcome measure indicating faster than expected patient adaptation. 
 
     
     
       20. The implantable medical device according to  claim 16 , wherein the neurostimulator is configured to receive a patient input indicating the side effect tolerance zone boundary by at least one of:
 receiving a radio frequency (RF) signal from an external communications device, said RF signal indicating that the patient has reached the side effect tolerance zone boundary, 
 detecting a magnetic field indicating that the patient has reached the side effect tolerance zone boundary, 
 detecting an acoustic signal indicating that the patient has reached the side effect tolerance zone boundary, or 
 detecting a motion signal with a motion sensor indicating that the patient has reached the side effect tolerance zone boundary.